This Information Applies To: Agilent Infinity II Vialsamplers G7129A/B/C.
High pressure in the Vialsampler is oftentimes due to a blockage in the needle seat assembly. The needle can pick up sample particulates or plugs from the vial caps when the Vialsampler is drawing the sample. When the valve switches back to mainpass, they are forced into the seat capillary and cause obstruction and high pressure.
Steps to follow:
To backflush the needle seat according to the following procedure, you need a pump with a manual purge valve. If you have a pump with an automatic purge valve, read the note below the article.
Using Lab Advisor (see How to Install Lab Advisor), go to the Service and Diagnostics section, click the Vialsampler, and click Injector Steps. Next, click Needle up for the Vialsampler to lift the needle (see Figure 1) up fully.
Warning: Avoid removing capillaries under high pressure, make sure to wear appropriate protective gear.
Disconnect the capillary in port 6 of the injection valve. Disconnect the seat capillary from port 5 in the injection valve and connect the needle seat capillary to port 6. The flow will go directly from the pump through the needle seat (make sure to work in bypass mode, use Figure 4 as a reference).
Keep the vialsampler in the Needle Up position.
In Lab Advisor under Injector Steps, click Needle Into Seat and then Reset to finish the procedure (Figure 5).
If the pressure is still high after the backflush, you will need a new seat. If you need more help, contact your local Agilent Technologies Support representative.
Note: If you have a pump with an automatic purge valve, you may disconnect and take out the needle seat completely. Connecting its capillary directly to the waste outlet of the switching valve of the pump and setting the pump to purge, you may thus flush backwards through the seat.
Learn how to effectively operate your Agilent Infinity II Vialsamplers:
Vialsamplers Agilent InfinityLab LC Series user manual on Agilent.com